Generally, Universal Serial Bus (USB) is a serial bus standard to the PC architecture with a focus on computer interface, consumer and productivity applications. The existing Universal Serial Bus (USB) interconnects have the attributes of plug-and-play and ease of use by end users. Now, as technology innovation marches forward, new kinds of devices, media formats and large inexpensive storage are converging. They require significantly more bus bandwidth to maintain the interactive experience that users have come to expect. In addition, the demand of a higher performance between the PC and the sophisticated peripheral is increasing. The transmission rate of USB 2.0 is insufficient. As a consequence, faster serial bus interfaces such as USB 3.0, are developed, which may provide a higher transmission rate so as to satisfy the need of a variety devices.
An existing USB 3.0 Type-B electrical receptacle connector includes an insulated housing, an upper tongue, and a lower tongue. The upper tongue and the lower tongue are arranged at the front part of the insulated housing. Upper-row contact terminals for USB 3.0 signal transmission are assembled to the upper tongue, and lower-row contact terminals for USB 2.0 signal transmission are assembled to the lower tongue. Therefore, the electrical receptacle connector is allowed to connect to an electrical plug connector. Generally, the legs of the contact terminals (the upper-row contact terminals and the lower-row contact terminals) are extended out of the rear part of the insulated housing and are further assembled to a positioning base at the rear part of the insulated housing. However, for the existing electrical receptacle connector having the positioning base, the matching between the positioning base and the insulated housing and the matching between the legs of the contact terminals and the positioning base have to be considered thoroughly so as to position the legs of the contact terminals steadily. In addition, the overall cost and the overall size of the electrical receptacle connector have to be considered as well.